Question

Two points $P$ and $Q$, diametrically opposite on a disc of radius $R$ have linear velocities $v$ and $2v$ as shown in figure. Find the angular speed of the disc.

• A. $\frac{v}{R}$
• B. $\frac{2v}{R}$
• C. $\frac{v}{2R}$
• D. $\frac{v}{4R}$

Answer 1

Answer: (C)

$\frac{v}{2R}$

$\begin{array}{c}\mu =\frac{-U_r}{PQ}=\frac{2V-V}{2R}=\frac{V}{2R}\\ \text{Rotation is clock wise so}\omega \text{is perpendicular}\\ \text{to paper inward}\end{array}$